<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<form action="mul" method="post">
  a:<input type="text" name="a">
  b:<input type="text" name="b">
  <input type="submit" value="提交">

</form>
</body>
</html>